Pressure means for lens lapping machine



Dec. 24, 1968 D. L. GRAY PRESSURE MEANS FOR LENS LAPPING MACHINE Filed May 2, 1966 INVENTOR DOLPH L. GRAY By WM ATTO N575 United States Patent 3,417,514 PRESSURE MEANS FOR LENS LAPPING MACHINE Dolph L. Gray, Muskogee, Okla., assignor to Coburn Manufacturing Company, Inc., Muskogee, Okla. Filed May 2, 1966, Ser. No. 547,015 1 Claim. (Cl. 51-216) ABSTRACT OF THE DISCLOSURE A device for holding a block having a lens secured thereto in engagement with a. rotating lap including a hollow cylinder mounted for lineal movement in .a housing, the cylinder having a cap at one end, a pin with one end engaging the block and the other end forming an expansion chamber with the cylinder and the cap, a spring in the chamber biasing the pin toward the block, and means to lock the cylinder in a selected position.

This invention relates generally to a sphere polisher and more specifically to improved sphere polishers for the polishing and fining of ophthalmic lenses. The improvement disclosed herein permits selection and maintenance of a constant spring bias pressure between lap and Workpiece for a period of time selected by the operator.

Polishers of the type described hereinafter are C0111! prised basically of a pre-selected, rotating, spherical polishing lap with means for maintaining a lens in engagement with the rotating lap. It is an objective of the invention to provide means for manually setting, adjusting and maintaining the pressure between the lap and workpiece during the polishing operation.

Another important objective of the invention is in the provision of spring bias regulated pressure means between lap and lens during the polishing operation.

A still further important objective of the invention is in the provision of mechanisms and controls to allow the experienced operator to select and maintain the necessary pressure between lens and lap to achieve superior polishing results.

These and other important objectives and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof and wherein: 1

FIGURE 1 is a perspective view;

FIGURE 2 is a side elevation partly in section of the apparatus shown in FIGURE 1;

FIGURE 3 is an exploded perspective view of the locking mechanism; and

FIGURE 4 is a section along the line 44 of FIG- URE 2.

Referring now to the drawings, wherein like elements are indicated by like numerals in the several views, the numeral indicates a lap which is replaceably mounted on a drive shaft (not shown) and which has a surface curve the same as the prescription curve to be formed on the surface of a lens 12. As is conventional in the polishing art, a block 14 is secured to one side of the lens. The rear of the block is formed with a central cone-shaped recess 16 for accepting a drive pin 18 which is tapered at 17. As will be understood more fully hereinafter, pin 18 maintains a pressure between the lens and lap as the polishing tool is rotated.

The upper end of the pin 18 forms a piston head 20 which is slidably received in a pressure cylinder 22. A spring 24 abuts against a threaded spring cap 26 and biases the pin downwardly. One side of the cylinder 22 forms a rack 28 of desired length which is engaged with a pinion 30. The pinion may be actuated by known means, here shown as a handle 32. The cylinder 22 is slidably received 3,41 7,5 14 Patented Dec. 24, 1968 in an elongated sleeve 31 of a housing 34. The supporting shaft 33 for pinion 30 is rotatably received in a journal 35. The block housing 34 is formed with an opening 37 between sleeve 31 and journal 35 permitting the pinion 30 to engage the rack 28. The housing 34 additionally receives a locking means to secure cylinder 22 at a selected height. The locking means comprises a bolt 36 having a right hand threaded portion, a left hand threaded portion and a handle 38 and locking nuts 40 and 41. The locking nuts are identical except that one has a right hand thread while the other has .a left hand thread and are respectively formed with inclined surface 42 and 42'. The locking nuts are received in a sleeve 41 of housing 34 and are assembled on the bolt 36 such that their inclined surfaces 42 and 42 face each other and can communicate with the cylinder 22 through an opening 43 between sleeves 31 .and 41. For purposes of clarity, the locking nut 41 shown in FIGURE 3 has been rotated out of the proper assembly position shown in FIGURE 4.

In operation, an operator selects a particular polishing lap with the proper curve and, when desired, attaches a polishing pad, .as known to the art. The lap is secured to a drive shaft making sure that it is snug and does not Wobble. The blocked lens is placed on the lap and pin 18 is lowered into engagement with recess 16 by rotating the pinion 30 by means of the handle 32. As the cylinder 22 is lowered, spring bias becomes greater. In this manner a trained operator varies the pressure between lens and lap until a desired pressure is obtained. This pressure is maintained by locking the cylinder 22 in place by simply rotating the handle 38. Such rotation draws locking nuts 40 and 41 toward one another thus gripping cylinder 22 between surfaces 42 and 42 and the sleeve 41.

There has been described a unit for the advantageous fining and polishing of ophthamalic lenses. The use of manually controlled spring pressure biasing means allows the trained operator to select and maintain the optimum polishing pressures for particular lenses.

In a general manner, while there has been disclosed an effective and efiicient embodiment of the invention, it should be well understood that the invention is not limited to such an embodiment, as there might be changes in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

I claim:

1. The structure for holding a block having a lens secured thereto in engagement with a rotating lap comprismg:

a housing having a first sleeve and a second sleeve,

a hollow cylinder slidably received in said first sleeve,

said second sleeve located adjacent said first sleeve with an opening therebetween,

a rack formed along the outer surface of said cylinder,

cap means threadably received in the upper end of said cylinder along the longitudinal axis of: the cylinder,

a pin having a lower end in driving engagement with said block and an upper end forming a sliding piston within said cylinder,

said cap means, a portion of said cylinder and said upper end forming an expansion chamber,

a spring received in said chamber and biasing said pin toward said block,

said cap means abutting said spring,

a pinion engaged with said rack,

means to rotate said pinion whereby the location of said cylinder with respect to said housing is adjustable,

a bolt receivable in said second sleeve,

said bolt having .a right hand threaded portion and a left hand threaded portion,

3,417,514-- I a v a 4 a.first nut threadably mounted on said right hand References Cited threaded portion, a second nut threadably mounted on said left hand UNITED STATES PATENTS threaded P 1,527,045 2/ 1925 Howland 51l24 I said first nut having a first carn surface portion protrud- 5 1 697 990 1/ 1929 Maynard ing through said opening adjacent a first portion of 2 225 040 12/1949 Dittmen said cylinder and said second nut having a second 2 371 52 2 1959 Dgsiato 51 124 cam surface portion protruding through said opening adjacent a second portion of said cylinder, and HAROLD D. WHITEHEAD, Primary Examiner. means to rotate said bolt whereby said first nut and 10 said second nut are drawn toward one another engag- US. Cl. X.Rr ing said first and second cam surface portions against 51-124 said first and second cylinder portions respectively. 

